Since 1990s, global energy crisis and environmental pollution have become more and more serious. Fossil oil accounts for more than 40% in the global total energy consumption, and according to the current proved reserves and consumption rate estimates, oil resources on the earth may be used up in the next few decades.
Motor vehicles are the major consumers of the oil and the major producers of air pollution. CO2 in the exhausts of the motor vehicles is one of the main sources of the greenhouse effect on the earth, and other components in the exhausts are also significant urban air pollutants.
Years of practice has proved that the use of novel fuels and novel power systems is an important way of solving the problem of vehicle energy bottlenecks and exhausts pollution. With respect to the novel fuels, the practice has proved that the use of alternative fuels, which are cleaner than gasoline and diesel, is a feasible solution to solve the problem of energy crisis and emission pollution. With respect to the novel power systems, pure electric vehicles using plumbic acid, nickel-hydrogen or lithium power storage batteries have the advantages of zero emission, low noise and high efficiency. However, due to the limitation of the electric energy storage technology, the pure electric vehicles not only have high manufacturing costs, but also have small cruising ranges and long charging time, and thus cannot really meet the use demands of people at present and in a relatively long future period and do not have enough market competitiveness. Therefore, a hybrid vehicle is used as a transitional vehicle between the traditional vehicle and the pure electric vehicle at present, the hybrid vehicle has some advantages of the both, such as ultra low emission, high efficiency and long cruising range, and only the cost is slightly higher than the vehicles that adopt traditional power systems. The power system of the hybrid vehicle includes a plurality of types, such as series, parallel and series-parallel types.
In the hybrid vehicle using the novel fuel in combination with electric power, as the novel fuel is generally stored in a corresponding fuel storage tank in a compression or a cooling compression manner. When the temperature in the external environment rises or when the vehicle is used not for a long time, the pressure of fuel in the fuel storage tank is liable to rise above a safe pressure thereof, for example, at the connection the fuel storage tank to the outside heat is liable to be absorbed and results in an increased pressure of the fuel in the fuel storage tank. This correspondingly brings a safety problem. At this time, to avoid the problem of the fuel storage tank, a pressure release valve is usually arranged at the fuel storage tank, which automatically opens when the pressure of the fuels in the fuel storage tank exceeds a certain threshold and releases a part of fuel into the surrounding atmosphere. Although the safety of the fuel storage tank is guaranteed in this way from a certain perspective, the combustible gas fuel leaked into the surrounding atmosphere will bring new potential safety problems, and it is also a waste of energy.